Inner valve turner
You screw a valve core tool onto the valve core of a car tyre, the inner valve that holds the air in. You use it during tyre repair, when replacing a valve and when filling with air or nitrogen. The size has to be right: a tool that sits too loose rounds off the core and then the valve leaks. There are plain versions, models with a T-handle and a valve core screwdriver with a torque gauge. That last one tightens the core to 0.4 Nm, so you do not overtighten it. A valve core remover with a metal inside grips a stuck core and pulls it out without damaging the thread. Order the size you need.
Which valve core tool you need
Which size fits your valve
Valve cores come in more than one size. Measure the old core or the tool you are used to before you order. A tool that sits too loose rounds off the core and then the valve leaks. There are plain valve core tools, models with a T-handle for more grip and a deluxe valve core tool with two sizes in one. Check which size fits your valves and stick to it.
When you need a torque gauge
You tighten a valve core by hand, but overtightening damages the thread. A valve core screwdriver with a built-in 0.4 Nm torque gauge tightens the core with the right force. Use it when fitting a new core, for example after replacing a valve.
Freeing a stuck core
If a valve core is stuck through corrosion or old rubber, a plain tool will round it off. A valve core remover with a metal inside grips the core harder and pulls it out without damaging the thread. Do not go straight in with full force: try soaking it loose first, then pull.
What you need alongside it
After removing a core you often need a new one. At valves you get the housing and the core as a set. A valve cap protects the core from dirt and moisture. For balancing the wheel you use wheel weights. Keep the tool with your tyre service kit so you can grab it straight away when a valve leaks.